Nuclear reactors

ABSTRACT

In a nuclear reactor, clamping means for clamping together a moving member and a fixed member against the effects of seismic shock comprise wedge devices mounted between fixed and moving members, the wedge devices comprising wedges adapted to be moved into contact with opposed surfaces of moving and fixed members by an actuating member operated by external means manually or automatically. The clamping means may be associated with a fuel charging machine.

United States Patent 9] Banks June 26, 1973 NUCLEAR REACTORS [75]Inventor: RobertBanks, Vicars Cross, England [73] Assignee: The NuclearPower Group Limited,

Knutsford, Cheshire, England [22] Filed: Dec. 3, 1970 [21] Appl. No.:94,748

[30] Foreign Application Priority Data 2,103,708 12/1937 Campbell 188/42X 2,970,445 2/1961 Suderow 188/44 X 3,263,377 8/1966 Pfeiffer 188/43 XFOREIGN PATENTS OR APPLICATIONS 217,726 111910 Germany 188/43 PrimaryExaminer-Duane A. Reger Attorney-l-1o1man & Stern [57] ABSTRACT In anuclear reactor, clamping means for clamping together a moving memberand a fixed member against the effects of seismic shock comprise wedgedevices mounted between fixed and moving members, the wedge devicescomprising wedges adapted to be moved into contact with opposed surfacesof movingand fixed members by an actuating member operated by externalmeans manually or automatically. The clamping means may be associatedwith a fuel charging machine.

2 Claims, 3 Drawing Figures PATENIEUmzS I973 3.741; 349

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ATTORNEYS PAIENIEnJuuzs 192s SHEET 3 F 5 3341.349

FIG. 3.

INVENTOR BYM ATTORNEYS NUCLEAR REACTORS BACKGROUND OF THE INVENTION 1.Field of the Invention This invention relates to nuclear reactors.

In reactors operating in areas where they may be subject to seismicshock it is necessary to provide means to clamp movable components so asto maintain them in predetermined relationships with fixed members. Thisis particularly the case with fuel charging devices which are arrangedto move over a fuel loading face of the reactor vessel and which aligncharging chutes with apertures in the vessel wall, which are in turnaligned with fuel element channels in the reactor core, to permit theloading or unloading of fuel elements.

Such fuel charging devices are mounted on gantries or guide railsforming part of the reactor vessel and are capable of movement in twomutually perpendicular directions in a horizontal plane. The chargingchute arrangement must be capable of vertical movement. By mounting thecharging device in this way it can be maneuvered over each of a numberof fuel element channels in the reactor core.

2. Summary of the Invention According to the present invention, a movingmember of the aforesaid fuel charging device is clamped in predeterminedrelationship with a fixed member of a nuclear reactor against theeffects of seismic shock by means of wedge means mounted between themoving and fixed members, the wedge means comprising wedges adaptedto bemoved into contact with opposed surfaces of moving and fixed members byan actuating member operated by external means manually orautomatically.

In one embodiment, each wedge means comprises two wedges separated by anactuating wedge the movement of which moves the other two wedges towardsor away from each other to exert clamping forces between opposedsurfaces of the moving and fixed members. Such actuating wedges may beoperated by hydraulic, pneumatic, electrical or mechanical means.

In a further embodiment of the invention a fuel charging devicecomprises a pair of cross members adapted to move along two guide rails,attached to the reactor vessel at right angles to the cross members, anda fuel charging member adapted to move along the cross members, in whichcharging device wedging means are located between the cross members andthe guide rails and between the fuel charging member and the crossmembers, said wedging means comprising wedges positioned on either sideof an actuating member the movement of which causes the wedges to moveapart to clamp the associated surfaces of the cross members and guiderails or the cross members and charging members as the case may be.

BRIEF DESCRIPTION OF THEDRAWINGS The invention also consists in aclamping arrangement for components of a nuclear reactor substantiallyas described herein with reference to the accompanying drawings, inwhich:

FIG. 1 is a longitudinal section through a fuel charging device inaccordance with one embodiment of the invention;

FIG. 2 is a plan view of the fuel charging device of.

FIG. 1;

FIG. 3 shows details of wedging devices incorporated in the fuelcharging device of FIGS. 1 and 2.

In carrying the invention into effect in the forms illustrated by way ofexample and referring first of all to FIGS. 1 and 2, a fuel chargingdevice for a nuclear reactor comprises a fuel charging member 1 adaptedto move along two cross members 2 and 3. The cross members are adaptedto move along guide rails on supports 4 and 5 which are attached topressure vessel 6 of a nuclear reactor.

The fuel charging member 1 can also be moved vertically so that itcan-be raised or lowered over apertures in the wall of the reactorvessel which apertures are aligned with fuel channels in the reactorcore in a known manner. The member 1 cooperated with a charging tube 7which is used to insert or collect (unload) fuel by means of a grab fromthe reactor.

The cross members run on wheels 8 along the guide rails 4 and 5 and thecharging member runs on wheels 9 along the cross members 2 and 3.

Wedging devices 10 and 11 are located between the fuel charging member 1and the cross members 2 and 3, while wedging devices 12 and 13 arelocated between the charging device gantry 14 and the guide railsupports 4 and 5.

The wedging means may be in the form shown in FIG. 3 comprising twowedges A and B located on either side of an actuating member C also inthe form of a wedge having a complementary taper to the taper of wedgesA and B.

When the fuel charging device is being moved, the wedges are located asshown in FIG. 3 where there is a clearance between wedge A and thesurface D with which clamping is to take place. When the actuatingmember C is moved, the wedge A moves into contact with the surface Dwith which it is associated and the wedges clamp together the twosurfaces in contact therewith i.e., the surfaces D and E in FIG. 3. Thesurfaces D and E would represent respectively the surfaces of crossmember and charging member or cross member and guide rail as the casemay be. If the actuating member moves for instance to the right in FIG.3 the wedge A is released and a clearance is again resumed permittingrelative movement between surfaces D and E.

In the form illustrated the actuating members are connected to hydraulicactuators 15. A hydraulic fluid can be supplied to the actuator 15 tomove the piston therein to the right or to the left.

In operation, when the fuel charging device is located over a fuelchannel the operator will operate the hydraulic actuators causing thewedge devices to clamp the gantry 14 and member 1 in position. Even if aseismic shock should then occur the clamping effect of the wedgingdevices maintains the predetermined relationship of charging device andreactor vessel.

If the charging device is moving when a seismic shock occurs thehydraulic actuator 15 can be operated automatically in response to asignal from a seismic shock detector to operate the wedging devices andeffect the necessary clamps.

The number of wedging members used is chosen to suit circumstancesrequirements in individual cases.

I claim:

1. A fuel charging apparatus for a nuclear reactor, comprising: a fuelcharging member having a plurality of rolling members and supportedthereby for linear movement in a first direction on a pair of spacedparallel elongated members forming a frame; a pair of parallel spacedguide rails disposed at right angles below said pair of spaced parallelelongated members, and means for enabling said frame to move linearly atright angles to said first direction on and guided by said guide rails;at least one wedging means which is the first wedging meansdisposed'between said fuel charging member and said frame forcontrollably arresting relative movement therebetween in said firstdirection; at least a second wedging means disposed between said frameand said spaced parallel guide rails for controllably arresting relativemovement therebetween in a direction at right angles to said firstdirection, said first wedging means including, a first wedging piecerigidly secured to said frame, a second wedging piece disposed adjacentand close to said fuel charging member so as to be moved into brakingcontact therewith, an immobile first central wedge piece disposed inbetween said first and second wedge pieces and having an axial taperwhich is substantially symetrical and complementary to said first andsecond wedge pieces, an actuating and supporting means connected to saidfirst central wedge piece for axially moving said first central wedgepiece so as to cause a a fourth wedging piece disposed adjacent andclose I to said frame so as to be moved into braking contact therewith,I

an immobile second central wedge piece disposed in between said thirdand fourth wedge pieces and having an axial taper which is substantiallysymetrical and complementary to said third and fourth wedge pieces,

a second actuating and supporting means connected to and for axiallymoving said second central wedge piece so as to cause a brakingengagement of said fourth wedging piece with the frame, thereby toarrest relative movement between said frame and the guide rails in saidsecond direction. v

2. A fuel charging apparatus as claimed in claim 1, wherein saidactuating and supporting means and said second actuatingsupporting meanseach comprise a piston and rod moving in a cylinder.

* III

1. A fuel charging apparatus for a nuclear reactor, comprising: a fuelcharging member having a plurality of rolling members and supportedthereby for linear movement in a first direction on a pair of spacedparallel elongated members forming a frame; a pair of parallel spacedguide rails disposed at right angles below said pair of spaced parallelelongated members, and means for enabling said frame to move linearly atright angles to said first direction on and guided by said guide rails;at least one wedging means which is the first wedging means disposedbetween said fuel charging member and said frame for controllablyarresting relative movement therebetween in said first direction; atleast a second wedging means disposed between said frame and said spacedparallel guide rails for controllably arresting reLative movementtherebetween in a direction at right angles to said first direction,said first wedging means including, a first wedging piece rigidlysecured to said frame, a second wedging piece disposed adjacent andclose to said fuel charging member so as to be moved into brakingcontact therewith, an immobile first central wedge piece disposed inbetween said first and second wedge pieces and having an axial taperwhich is substantially symetrical and complementary to said first andsecond wedge pieces, an actuating and supporting means connected to saidfirst central wedge piece for axially moving said first central wedgepiece so as to cause a braking engagement of said second wedge piecewith the fuel charging member, thereby to arrest relative movementbetween the frame and said fuel charging member; said second wedgingmeans including, a third wedging piece rigidly secured to said guiderails, a fourth wedging piece disposed adjacent and close to said frameso as to be moved into braking contact therewith, an immobile secondcentral wedge piece disposed in between said third and fourth wedgepieces and having an axial taper which is substantially symetrical andcomplementary to said third and fourth wedge pieces, a second actuatingand supporting means connected to and for axially moving said secondcentral wedge piece so as to cause a braking engagement of said fourthwedging piece with the frame, thereby to arrest relative movementbetween said frame and the guide rails in said second direction.
 2. Afuel charging apparatus as claimed in claim 1, wherein said actuatingand supporting means and said second actuating supporting means eachcomprise a piston and rod moving in a cylinder.